Sen. Ted Cruz holds a 9-point lead over U.S. Rep. Beto O'Rourke in the Texas Senate race, according to a Quinnipiac University poll released Tuesday morning.

The incumbent Cruz has a 54-45 likely lead over O'Rourke. The poll was Quinnipiac's first survey of likely Texas voters.

Among the likely voters polled, 93 percent said they had made their mind up over who they'll be voting for. Republicans supported Cruz 94 to 6 percent in the poll, while Democrats backed O'Rourke 94 to 4.

Independent voters were nearly split, with 51 percent supporting O'Rourke and 47 percent supporting Cruz.

While the race has "boosted talk of a Senate takeover," said Quinnipiac assistant poll director Peter A. Brown, "these numbers may calm that talk."

"Congressman O'Rourke may be drawing big crowds and media attention," Brown said, "but Texas likely voters like Sen. Cruz better."

Immigration was the most important issue in the poll, according to 27 percent of likely Texas voters, the poll reported. Health care (21 percent), the U.S. Supreme Court (16 percent) and the economy (15 percent) were the other top issues.